This TurboTax Help states:
Do I need to do anything to get my stimulus check?
You don’t need to do anything to get the third stimulus check. The IRS will determine eligibility based on your last tax return (either 2019 or 2020) and will likely send your payment to the bank account where your tax refund was deposited.
The IRS says that the only way to update your mailing address and banking information is by filing your 2020 Federal 1040 tax return. The IRS is making no portal available.
If your 2020 Federal 1040 tax return was accepted, we do not know whether the IRS will issue a third stimulus payment using 2019 tax information or 2020 tax information.
The IRS is sending the Third Economic Impact Payments in accordance with the American Rescue Plan Act of 2021, signed into law on March 11, 2021. Check when and how your payment was sent with the Get My Payment tool.
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